滚雪球效应原理

简介：These two materials are not self-sufficient in Liaodong, and they are also strategic materials that are very scarce and strictly controlled by the Ming Dynasty and will never be allowed to flow to the Jianlu. However, according to Xiao Hanjun's secret investigation, there is not a small amount of grain, sulfur and saltpeter flowing to Liaodong through Zhangjiakou every year.